Therefore after Moses had wrote the words of this law in a volume, and finished it:

And it came to pass, when Moses had ended writing the words of this law in a book, until their conclusion,

And it cometh to pass, when Moses finisheth to write the words of this law on a book till their completion,

Now after writing all the words of this law in a book till the record of them was complete,

It happened, when Moses had made an end of writing the words of this law on a scroll, until they were finished,

Therefore, after Moses had written the words of this law in a volume, and had finished it,

Quum autem fecisset finem Moses scribendi verba legis istius in libro, donec ea complerentur,

And it came to pass, when Moses had made an end. By "the words of this law," we must understand not only those which are embraced in this book, but in the other three also; and there is an implied antithesis between the two tables written by God's hand, and the exposition which was afterwards added, lest there should be any obscurity respecting God's will on account of the brevity with which it was delivered. At the very beginning, indeed, God had set forth whatever it was useful for them to know, but it was His will that what He had briefly comprehended in the Decalogue should be more fully unfolded, and not only so, but that it should be also committed to writing, lest it should be forgotten. We know how inclined to vanity is the mind of man, nay, how willfully it is led away into error by its levity; whilst it has other faults also, such as inquisitiveness, and audacity in invention, and the love of novelty. Thus religion would have been corrupted in a thousand ways, had not its rule been diligently written down for posterity. Moreover, since the books of Moses were for a long time buried through the carelessness of the people and the priests, what darkness of error would have overspread the minds of all, if nothing had been written down! Since the two Tables were enclosed in the Ark of the Covenant, a place at the side was assigned to the interpretation, so that they might have no doubt but that it proceeded from the same Divine Author; and, since the Decalogue is repeated in these books, it was not at all necessary that the Ark should be opened; which was not lawful, because they might seek in the books of Moses the instruction which was hidden in the Tables. This, indeed, we must remember, that the volume was placed near the Ark in token of its dignity, so that, when it was taken from thence by the Levites, it might be listened to with greater reverence. When it is said, "That it may be there for a witness against thee," this is not addressed to the Levites alone, but relates generally to the whole people, though the general statement is directed to them as one member of the whole body. But further, although the application of its doctrine is manifold, still one point only is adverted to; for the Law was not written with the single object of being a witness to condemn the people, but to be the rule of a pious and holy life, and a testimony of God's favor. But, since he had to do with hard and proud minds, Moses declares that, whenever its doctrine shall be set forth, it will render their perverseness inexcusable.

Moses completes the writing out of the book of the Law, and directs it to be placed by the ark of the covenant.

The "book" here spoken of would contain the whole Pentateuch up to this verse, and be "the Book of Moses," called generally by the Jews "the Law" (compare Matthew 22:40; Galatians 4:21).

And it came to pass, when Moses had made an end of writing the words of this law in a book,.... In this book of Deuteronomy, and which concluded the Pentateuch:
until they were finished; all the words of the law, and the whole five books of Moses, excepting some few verses, Deuteronomy 34:1, which were added by another hand, Joshua or Ezra.

With the installation of Joshua on the part of God, the official life of Moses was brought to a close. Having returned from the tabernacle, he finished the writing out of the laws, and then gave the book of the law to the Levites, with a command to put it by the side of the ark of the covenant, that it might be there for a witness against the people, as He knew its rebellion and stiffneckedness (Deuteronomy 31:24-27). על־ספר כּתב, to write upon a book, equivalent to write down, commit to writing. תּמּם עד, till their being finished, i.e., complete. By the "Levites who bare the ark of the covenant" we are not to understand ordinary Levites, but the Levitical priests, who were entrusted with the ark. "The Levites" is simply a contraction for the full expression, "the priests the sons of Levi" (Deuteronomy 31:9). It is true that, according to Numbers 4:4., the Kohathites were appointed to carry the holy vessels, which included the ark of the covenant, on the journey through the desert; but it was the priests, and not they, who were the true bearers and guardians of the holy things, as we may see from the fact that the priests had first of all to wrap up these holy things in a careful manner, before they handed them over to the Kohathites, that they might not touch the holy things and die (Numbers 4:15). Hence we find that on solemn occasions, when the ark was to be brought out in all its full significance and glory, - as, for example, in the crossing of the Jordan (Joshua 3:3., Deuteronomy 4:9-10), when encompassing Jericho (Joshua 6:6, Joshua 6:12), at the setting up of the law on Ebal and Gerizim (Joshua 8:33), and at the consecration of Solomon's temple (1-Kings 8:3), - it was not by the Levites, but by the priests, that the ark of the covenant was borne. In fact the Levites were, strictly speaking, only their (the priests') servants, who relieved them of this and the other labour, so that what they did was done in a certain sense through them. If the (non-priestly) Levites were not to touch the ark of the covenant, and not even to put in the poles (Numbers 4:6), Moses would not have handed over the law-book, to be kept by the ark of the covenant to them, but to the priests. ארון מצּד, at the side of the ark, or, according to the paraphrase of Jonathan, "in a case on the right side of the ark of the covenant," which may be correct, although we must not think of this case, as many of the early theologians do, as a secondary ark attached to the ark of the covenant (see Lundius, Jd. Heiligth. pp. 73, 74). The tables of the law were deposited in the ark (Exodus 25:16; Exodus 40:20), and the book of the law was to be kept by its side. As it formed, from its very nature, simply an elaborate commentary upon the decalogue, it was also to have its place outwardly as an accompaniment to the tables of the law, for a witness against the people, in the same manner as the song in the mouth of the people (Deuteronomy 31:21). For, as Moses adds in Deuteronomy 31:27, in explanation of his instructions, "I know thy rebelliousness, and thy stiff neck: behold, while I am yet alive with you this day, ye have been rebellious against the Lord (vid., Deuteronomy 9:7); and how much more after my death."
With these words Moses handed over the complete book of the law to the Levitical priests. For although the handing over is not expressly mentioned, it is unquestionably implied in the words, "Take this book, and put it by the side of the ark of the covenant," as the finishing of the writing of the laws is mentioned immediately before. But if Moses finished the writing of the law after he had received instructions from the Lord to compose the ode, what he wrote will reach to Deuteronomy 31:23; and what follows from Deuteronomy 31:24 onwards will form the appendix to his work by a different hand.
(Note: The objection brought against this view by Riehm, namely, that "it founders on the fact that the style and language in Deuteronomy 31:24-30 and Deuteronomy 32:44-47 are just the same as in the earlier portion of the book," simply shows that he has not taken into consideration that, with the simple style adopted in Hebrew narrative, we could hardly expect in eleven verses, which contain for the most part simply words and sayings of Moses, to find any very striking difference of language or of style. This objection, therefore, merely proves that no valid arguments can be adduced against the view in question.)
The supposition that Moses himself inserted his instructions concerning the preservation of the book of the law, and the ode which follows, is certainly possible, but not probable. The decision as to the place where it should be kept was not of such importance as to need insertion in the book of the law, since sufficient provision for its safe keeping had been made by the directions in Deuteronomy 31:9.; and although God had commanded him to write the ode, it was not for the purpose of inserting it on the Thorah as an essential portion of it, but to let the people learn it, to put it in the mouth of the people. The allusion to this ode in Deuteronomy 31:19. furnishes no conclusive evidence, either that Moses himself included it in the law-book which he had written with the account of his oration in Deuteronomy 31:28-30 and Deut 32:1-43, or that the appendix which Moses did not write commences at Deuteronomy 31:14 of this chapter. For all that follows with certainty from the expression "this song" (Deuteronomy 31:19 and Deuteronomy 31:22), which certainly points to the song in ch. 32, is that Moses himself handed over the ode to the priests with the complete book of the law, as a supplement to the law, and that this ode was then inserted by the writer of the appendix in the appendix itself.